A fiber-testing instrument commonly known in the textile industry as AFIS (Advanced Fiber Information System) is manufactured by Zellweger Uster, Inc., Knoxville, Tenn. This equipment in now being used world-wide as a textile process quality control tool to optimize processing machinery. Further, its value and use as a tool to optimize textile raw materials purchase and allocation is increasing. For both applications, the primary performance factors are relevance of the data products, reproducibility, testing speed, ease of use, and costs. It is not essential that the measurement be absolute. However, it was a goal from the outset to make AFIS basic and absolute. One of the fundamentally important reasons for this goal was to improve basic understandings of the fiber to yarn engineering process.
Further experience with the AFIS instrument has confirmed that it will indeed become the reference method for providing distributions of nep and trash entities. Importantly here, AFIS can become the absolute reference for distributions of fiber length, diameter, fineness, and maturity provided certain improvements are made. The primary improvement needed in the electro-optical sensor relates to fibers which are presented in a looped condition (fiber folded back on itself). Such looped fibers can be excluded from the data product on the basis of their waveform characteristics, as is done currently, but the AFIS method becomes more basic, more absolute, and faster if loops are prevented or delooped by fluid dynamic means or if looped fiber waveforms are electronically corrected. We have discovered both fluid dynamic and electronic methods for achieving these "delooping" results.
Some of the fibers delivered pneumatically to the sensor from a fiber individualizer (described in U.S. Pat. Nos. 4,512,060; 4,631,781; and 4,686,744) are known to be looped or hooked because of the nature of the pinned cylinders, carding flats, and other elements of the entity individualization process. Further, the Reynolds numbers of the transporting and accelerating flows are sometimes deep within the turbulent flow regime. Whereas such high speed flows are advantageous for testing speed and for stretching the fiber (to remove crimp), there is, in general, substantial looping of the fibers.
One objective of the present invention is to match fluid flow to a nozzle in an "AFIS" type instrument to maximize the number of entities, such as fibers, that are presented in a desired orientation. For example, the fluid flow should be selected to optimize the number of fibers that are presented to a sensor in a straight (non-looped) condition. If a fiber is presented to a sensor in a looped condition (folded back on itself), it increases the difficulty of measuring various fiber parameters, such as fiber length.
However, even with optimal flow conditions for an AFIS type sensor, a substantial number of fibers were presented to the sensor in a looped condition. Thus, an investigation was begun to improve the presentation properties of the AFIS1 nozzle following the teachings of a paper entitled "Basic Investigation of the Behavior of Cottons Subjected to Aerodynamic Forces, For the Purpose of Improving the Processing Characteristics of Cotton Textiles," Tryggve Eeg-Olofsson, Gothenburg, Sweden (January, 1969) which was found in the Roger Milliken Textile Library, Institute of Textile Technology, Charlottesville, Va. 22902 (TX 262, E26, 1969). Efforts to improve the presentation characteristics of the nozzle met with little or no success, and it was eventually discovered that the teachings of the aforementioned paper were not applicable to the AFIS nozzle for unknown reasons. In fact, it was discovered that the AFIS nozzle could be improved by a design that apparently directly contradicted the teachings of the aforementioned paper, it being understood that the AFIS nozzle is necessarily different in structure and operates in a different environment for a different purpose, than the nozzles investigated in the aforementioned paper.
Even with the improved nozzle of the present invention, in combination with the matching airflow and air condition of the present invention, some looping of the fibers persisted. Thus, electronic means were developed to electronically "deloop" the fibers, as hereinafter described in greater detail.
Accordingly, it is one objective of this invention to provide flow control means by which flows in the fiber individualizer and sensor(s) can be more generally and optimally matched to improve conditions and to minimize looping and maximize data rate. It is a further objective of the invention to provide accelerating nozzle means which deloop fibers, and it is a final objective to provide electronics means to "electronically-deloop" by analyzing sensor signal waveforms produced by looped fibers.